The field of medication delivery devices and systems includes “syringe pumps,” which are typically pre-filled medication syringes mechanically driven under microprocessor control to deliver a prescribed dose of medication at a controlled rate to a patient through an infusion line fluidly connected to the syringe. A syringe pump typically includes a motor that rotates a leadscrew. The leadscrew in turn activates a plunger driver which forwardly pushes a plunger within a barrel of the syringe. Pushing the plunger forward thus forces the dose of medication outwardly from the syringe, into the infusion line, and to the patient intravenously or via any other suitable route. As used throughout this disclosure, the term “syringe pump” is intended to generally pertain to any medical device which acts on a syringe to controllably force fluid outwardly therefrom.
Typically in syringe pumps, a force sensor is positioned adjacent a syringe thumbpress in order to measure a force with which the pump is pushing on the syringe. This measured force can be used to determine fluid pressure inside the syringe which may be, for example, indicative of an undesirable downstream occlusion. While a force sensor adjacent the thumbpress is typically satisfactory for relatively large syringe pumps such as those that are provided near patient beds or otherwise employed in hospitals and clinical settings, it can be unsatisfactory or otherwise problematic for relatively small devices such as, for example, ambulatory syringe pumps wherein provision of a relatively compact device with an acceptable ingress protection rating may be of particular concern.
Attempts to address these problems or deficiencies have resulted in placing a force sensor internal to the pump to determine the fluid pressure. Another attempted approach is to place a force sensor in the moving plunger head and measure the syringe force directly. However, a separate sensor is then required to determine the correct placement or seating of the syringe thumbpress. One approach entails providing digital or analog thumbpress sensors as a component separate from the force sensor where the digital switch confirms that the thumbpress is in the correct position and the analog device measures the size of the thumbpress and verifies that it falls within the correct range. In addition, many syringe pumps further include a separate sensor that measures the linear position of the plunger head.
One problem with the above conventional approaches is that there exists relative motion between a main printed circuit board and the sensor, resulting in a moving electrical connection or moving wires between a component in motion (e.g., force sensor or thumbpress sensor) and a static component (e.g., main printed circuit board). Another problem is that numerous separate components must be provided which subsequently results in a more complex system.
Consequently, it would be useful and advantageous to provide systems and methods that solve the problems associated with syringe pumps as discussed above.